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package javax.xml.bind.attachment;

import javax.activation.DataHandler;
import javax.xml.bind.Marshaller;

/**
 * <p>Enable JAXB marshalling to optimize storage of binary data.</p>
 *
 * <p>This API enables an efficient cooperative creation of optimized
 * binary data formats between a JAXB marshalling process and a MIME-based package
 * processor. A JAXB implementation marshals the root body of a MIME-based package,
 * delegating the creation of referenceable MIME parts to
 * the MIME-based package processor that implements this abstraction.</p>
 *
 * <p>XOP processing is enabled when {@link #isXOPPackage()} is true.
 * See {@link #addMtomAttachment(DataHandler, String, String)} for details.
 * </p>
 *
 * <p>WS-I Attachment Profile 1.0 is supported by
 * {@link #addSwaRefAttachment(DataHandler)} being called by the
 * marshaller for each JAXB property related to
 * {http://ws-i.org/profiles/basic/1.1/xsd}swaRef.</p>
 *
 * @author Marc Hadley
 * @author Kohsuke Kawaguchi
 * @author Joseph Fialli
 * @see Marshaller#setAttachmentMarshaller(AttachmentMarshaller)
 * @see <a href="http://www.w3.org/TR/2005/REC-xop10-20050125/">XML-binary Optimized Packaging</a>
 * @see <a href="http://www.ws-i.org/Profiles/AttachmentsProfile-1.0-2004-08-24.html">WS-I
 * Attachments Profile Version 1.0.</a>
 * @since JAXB 2.0
 */
public abstract class AttachmentMarshaller {

  /**
   * <p>Consider MIME content <code>data</code> for optimized binary storage as an attachment.
   *
   * <p> This method is called by JAXB marshal process when {@link #isXOPPackage()} is
   * <code>true</code>, for each element whose datatype is "base64Binary", as described in Step 3 in
   * <a href="http://www.w3.org/TR/2005/REC-xop10-20050125/#creating_xop_packages">Creating XOP
   * Packages</a>.
   *
   * <p> The method implementor determines whether <code>data</code> shall be attached separately or
   * inlined as base64Binary data. If the implementation chooses to optimize the storage of the
   * binary data as a MIME part, it is responsible for attaching <code>data</code> to the MIME-based
   * package, and then assigning an unique content-id, cid, that identifies the MIME part within the
   * MIME message. This method returns the cid, which enables the JAXB marshaller to marshal a XOP
   * element that refers to that cid in place of marshalling the binary data. When the method
   * returns null, the JAXB marshaller inlines <code>data</code> as base64binary data.
   *
   * <p> The caller of this method is required to meet the following constraint. If the element
   * infoset item containing <code>data</code> has the attribute <code>xmime:contentType</code> or
   * if the JAXB property/field representing <code>data</code>is annotated with a known MIME type,
   * <code>data.getContentType()</code> should be set to that MIME type.
   *
   * <p> The <code>elementNamespace</code> and <code>elementLocalName</code> parameters provide the
   * context that contains the binary data. This information could be used by the MIME-based package
   * processor to determine if the binary data should be inlined or optimized as an attachment.
   *
   * @param data represents the data to be attached. Must be non-null.
   * @param elementNamespace the namespace URI of the element that encloses the base64Binary data.
   * Can be empty but never null.
   * @param elementLocalName The local name of the element. Always a non-null valid string.
   * @return a valid content-id URI (see <a href="http://www.w3.org/TR/xop10/#RFC2387">RFC 2387</a>)
   * that identifies the attachment containing <code>data</code>. Otherwise, null if the attachment
   * was not added and should instead be inlined in the message.
   * @see <a href="http://www.w3.org/TR/2005/REC-xop10-20050125/">XML-binary Optimized Packaging</a>
   * @see <a href="http://www.w3.org/TR/xml-media-types/">Describing Media Content of Binary Data in
   * XML</a>
   */
  public abstract String addMtomAttachment(DataHandler data, String elementNamespace,
      String elementLocalName);

  /**
   * <p>Consider binary <code>data</code> for optimized binary storage as an attachment.
   *
   * <p>Since content type is not known, the attachment's MIME content type must be set to
   * "application/octet-stream".</p>
   *
   * <p> The <code>elementNamespace</code> and <code>elementLocalName</code> parameters provide the
   * context that contains the binary data. This information could be used by the MIME-based package
   * processor to determine if the binary data should be inlined or optimized as an attachment.
   *
   * @param data represents the data to be attached. Must be non-null. The actual data region is
   * specified by <tt>(data,offset,length)</tt> tuple.
   * @param offset The offset within the array of the first byte to be read; must be non-negative
   * and no larger than array.length
   * @param length The number of bytes to be read from the given array; must be non-negative and no
   * larger than array.length
   * @param mimeType If the data has an associated MIME type known to JAXB, that is passed as this
   * parameter. If none is known, "application/octet-stream". This parameter may never be null.
   * @param elementNamespace the namespace URI of the element that encloses the base64Binary data.
   * Can be empty but never null.
   * @param elementLocalName The local name of the element. Always a non-null valid string.
   * @return content-id URI, cid, to the attachment containing <code>data</code> or null if data
   * should be inlined.
   * @see #addMtomAttachment(DataHandler, String, String)
   */
  public abstract String addMtomAttachment(byte[] data, int offset, int length, String mimeType,
      String elementNamespace, String elementLocalName);

  /**
   * <p>Read-only property that returns true if JAXB marshaller should enable XOP creation.</p>
   *
   * <p>This value must not change during the marshalling process. When this value is true, the
   * <code>addMtomAttachment(...)</code> method is invoked when the appropriate binary datatypes are
   * encountered by the marshal process.</p>
   *
   * <p>Marshaller.marshal() must throw IllegalStateException if this value is <code>true</code> and
   * the XML content to be marshalled violates Step 1 in <a href="http://www.w3.org/TR/2005/REC-xop10-20050125/#creating_xop_packages">Creating
   * XOP Pacakges</a> http://www.w3.org/TR/2005/REC-xop10-20050125/#creating_xop_packages.
   * <i>"Ensure the Original XML Infoset contains no element information item with a [namespace
   * name] of "http://www.w3.org/2004/08/xop/include" and a [local name] of Include"</i>
   *
   * <p>When this method returns true and during the marshal process at least one call to
   * <code>addMtomAttachment(...)</code> returns a content-id, the MIME-based package processor must
   * label the root part with the application/xop+xml media type as described in Step 5 of <a
   * href="http://www.w3.org/TR/2005/REC-xop10-20050125/#creating_xop_packages">Creating XOP
   * Pacakges</a>.<p>
   *
   * @return true when MIME context is a XOP Package.
   */
  public boolean isXOPPackage() {
    return false;
  }

  /**
   * <p>Add MIME <code>data</code> as an attachment and return attachment's content-id, cid.</p>
   *
   * <p>
   * This method is called by JAXB marshal process for each element/attribute typed as
   * {http://ws-i.org/profiles/basic/1.1/xsd}swaRef. The MIME-based package processor
   * implementing this method is responsible for attaching the specified data to a
   * MIME attachment, and generating a content-id, cid, that uniquely identifies the attachment
   * within the MIME-based package.
   *
   * <p>Caller inserts the returned content-id, cid, into the XML content being marshalled.</p>
   *
   * @param data represents the data to be attached. Must be non-null.
   * @return must be a valid URI used as cid. Must satisfy Conformance Requirement R2928 from <a
   * href="http://www.ws-i.org/Profiles/AttachmentsProfile-1.0-2004-08-24.html#Referencing_Attachments_from_the_SOAP_Envelope">WS-I
   * Attachments Profile Version 1.0.</a>
   */
  public abstract String addSwaRefAttachment(DataHandler data);
}
